Automatic hoist.



G. C. GRABLB.

AUTOMATIC HOIS'I'.

APPLIOATION FILED 1211.111. 11107,

Patented Jan.31,1911.

2 BHEETS--BHEET 1.

G. C. GRABLB.

AUTOMATIC HOIST.

APPLIUATION FILED Amma, 19074 Patented Ja,11.31, 1911.

2 SHEETS-SHEET 2.

Maz/ML,

rHs'NaRms FErERs cc., wAsHmoruN, D. c,

vUivrrni) s'rA'igEs PATENT OFFICE.

GUY C. GRABLE, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO NELSON F. DUNN, 0F MINNEAPOLIS, MINNESOTA.

AUTOMATIC I-IOIST.

Specification of Letters Patent.

Patented Jan. 31, 1911.

To all whom it may concern:

Be it. known that l, GUY C. GRABLE, a citizen of the United States, residing at Minneapolis, in the county of lilennepin and State of Minnesota, have invented certain new and useful Improvements in Au tomatic Hoists; and I do hereby declare the following to b-e a full, clear, and exact dcscription of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention has for its object to provide an improved automatic hoist especially adapted for use in the erection of buildings for elevating the building material from the ground to one of the upper stories.

More particularly stated, this invention relates to hoist-s of this character which employ rcversely movable cars, frequently designated as scales, which are arranged the one' to approximately counter balance the other, and the one to move upward while the other is moving downward.

The chief feature of my present invention is directed to an electrical controlling mechanism for controlling and regulating the movements of the cars or scales.

This improved mechanism, as well as other minor but novel features of this invention are illustrated in the drawings and will be hereinafter' described and defined in the claims.

In the drawings like characters indicate like parts throughout the severa-l views.

Jreferring to the drawings, Figure 'l is a view partly in elevation and partij,T in section and with some parts shown in diagram only, showing a hoisting` mechanism to which my invention is applied. F ig. 2 is a view partly in elevation, but principally in diagram, illustrating the construction and arrangement of the automatic electrical controlling mechanism. Fig. 3 is a detail in elevation, showing one of the stop switches. Fig. l is a plan view of the parts shown in Fig. 3, some parts being broken awa-y. Fig. 5 is a plan view, showingV the windlass mechanism and motor for driving the same. Fig. 6 is a side elevation of the parts shown in Fig. 5. Fig. 7 is a vertical section taken on the line a, m7 of Fig. 5. Fig. 8 is a section taken approximately on the line 'ws .es of Fig. 7 and F ig. 9 is a detail in section on the irregular line m9 m of Fig. 7, some parts being broken away.

The numeral 1 indicates what may be designated as the floor of the first story, and the numeral 2 the floor of one of the upper stories, the latter having an opening 8 through which the cars or so-called scales are adapted to pass. These cars or scales ll, as shown, are guided for vertical movements by vertical guide cables 5 attached to the floor 1, and at their upperI ends to a framework 6 which is supported by the floor 2 and is frequently designated as the horse. The two cars l are attached one to each end of a hoisting cable 7, which cable is passed over guide sheaves 8 on the horse 6, under guide sheaves 9 journaled to the floor 1 and around a driving sheave 10, around which latter the cable is given several turns so as to give the proper friction between the said cable and driving sheave. This driving sheave 10 is loosely journaled on a shaft 11 of the windlass mechanism which shaft, as shown, is mounted in suitable bearings 12 on a suitable supporting base or frame 13. The sheave 10 is shown as provided with a brake drum 11i and with a half-clutch 15 with which half-clutch cooperates a sliding half-clutch 16 located on but carried by the shaft 11. The half-clutch 16 is adapted to be thrown into and out of engagement with the half-clutch 15, at will, by means of a shipper lever 17, shown as pivoted to a lug 1S on one of the bearings 12. A brake strap 19 of the usual construction cooperates wit-h the brake drum 14 and is adapted to be operated in the usual way by a lever 20, to which the ends of said strap are eccentrically pivoted.

The motor is of the usual construction, and of the parts thereof it is only desirable for the purposes of this case to note the combined case and supporting frame 21, which is shown as secured to the base frame 13, and the armature 22, the shaft of which at one end carries a spur pinion 23, and at its other' end a brake drum 24. In the arrangement shown, the pinion 23 meshes with an intermediate gear 25, journaled on a bearing 26 secured to the base frame 13, and this intermediate gear 25 meshes with a large spur gear 27 secured to the windlass shaft 11.

For coperation with the brake drum 24 of the armature shaft, a pair of metallic brake straps 28 are provided, and these, as shown, 'are pivotally supported at their upper ends by a bracket 29 rigidly secured to the motor case. or frame 2 A nutted bolt El() is passed through the depending endsI of the brake straps 28, and a coiled spring ll `is compressed between the. end of said bult and the depending end of the adjacent strap 28. rthe force of this spring -li will clamp the brake straps 28 onto the drinn 24 with. sulicient force to stop the motor and pre vent rotation of the armature thereof, both under the magnetic driving force and the reverse force imparted thereto by the weight of the load. The brake straps 28 are adapted to be forced apart and away fromthe drum 24, against the tension of the spring 3l, by the cani acting head 32 of a pivoted armature equipped lever 83, shown in Fig. 6, when the armature of said lever is drawn toward the right with respect to Fig. by a magnet 34, which magnet, as will presently be noted, is connected in z-aeries with the armature of the motor.

On the intermediate portion of the windlass shaft ll is a loosely journaled windlass drum 35, one rim of which is formed with an internal groove Si), the purpose of which will presently appear. The driving gear 27 is provided with one or more, as shown with three, rigidly secured bearing brackets 37 that project int-o the -concave flange of the windlass drum 35. Journaled in the projectingl end of each bracket 37 is a short rock shaft 38 disposed radially with respect to the axis of the windlass shaft l1. At thei1 outer ends, the rock shafts 38 are provided with T-heads cr dian'ietrically extended arms 89, on both ends of which are mounted small clutch shoes 4() that are adapted to bear against the opposite sides of the annular channel 3G, as best shown in Figs. 7 and t). At their inner ends the said rock shafts 88 are provided with armature equipped arms 4l that are subject to magnet coils 42 located adjacent thereto and carried by the driving gear 27. The terminals of the magnet coils 42 are connected to contact rings 43 and 44 carried by the gear 27, and these contact rings are in constant engagement, respectively, with relatively fixed brushes 48 and 44a. As is evident, when the coils 42 are 4magnetize'd the rock shafts 38 and 39 will be oscillated and the clutch shoes 40 will be pressed against the opposite sides of the channel 36, thereby frictienally coupling the windlass drum 35 to the driving gear 27. The manner in which this is accomplished will hereinafter more clearly appear. As shown, the windlass shaft ll is provided at one end with a capstan 4G of the usual construction.

The so-called tripping contacts .are preferably arranged in upper and lower pairs there being two such contacts in each car or scale 4. As shown in the drawings, each of these tripping contacts comprises a lever 47 and coperatmg rocker arm 48 pivotally supported by a cross bar 4S) of the vertical supporting rod 5t). This supportingI rod 5() may be rigidly supported in any suitable way from the lioor 2 with one pair of tripping contacts above the lloor and one pair below the same although, of course, this arrangement may be varied. The levers 47 are shown as provided with insulated free ends 5l that are adapted to be engaged by thc corresponding car or scale 4 under .upward movements of the latter, and to be thereby forced into inoperative positions shown in Figs. 2 and 3. Qn the rock-er arms 48 are push lugs 48ZL which when moved upward are adapted to force the cooperating levers 47 downward into operative positions. The vertically alined rocker arms 48 are connected for common movements by operating rods Then the upperleft hand contact lever 47 is moved downward into an operative position it engages with the contact 53; when the lower left hand contact lever 47 is thus moved into an operative position it engages a contact 54; when the lower right hand Contact 47 is moved into an operative position it engages with a contact and when the upper' right hand contact lever 47 is moved into operative position it engages with two contacts and 57.

The current which supplies the motive force is conveyed by supply leads 58 and 59. The lead 58, as shown, includes the coil of the brake magnet (see Fig. 2) and eX- tends to one terminal of the motor armature 22 through the usual commutator connection.

The numerals G0, 61, G2 and G3 indicate fixed contacts of the mot-or reversing switch, which contacts are arranged in pairs constituting upper and a lower series.

The numeral G4 indicates the movable contact of the said switch. This movable contact G4 is carried by a core G9, which latter is arranged to be moved vertically by a solenoid (see Fig. 2).

In Fig. 2 the numeral 7l indicates a rheostat of standard construction, and the numeral 72 indicates a series of relatively Fixed rheostat controlling contacts.

The numeral 73 indicates the rheostat con* trolling lever, to the end of which, as shown, is pivoted a small bell crank 74 carrying a conta-ct wheel 75 at the free end of its arms. This contact wheel 7 5 moves over the fixed contact 72. The other arm of said bell crank 74 is, as shown, connected by a short link 7 6 to a core 77 which is arranged to be actuated by a pair of solenoids 78 and 7 9. The movements of the controlling lever 73 are preferably retarded by an ordinary cyl inder and piston dash pot 80.

The wire 59 which constitutes one of the supply leads extends t-o the upper member of the fixed rheostat controlling contact 72, and from this upper fixed conta-ct or from of throwing more of the coils of the rheostat 7l into circuit. with the motor, thereby increasing the resistance of the motor circuit and causing the motor to materially slow down. 1V hen the said right hand car, under continued upward movement, very closely approaches the limits of its extremo upward n'iovenient, it comes into contact with the upper right hand contact levell t7 and thereby moves the same into its raised or inoperative position, thus moving the same out of engagement with the contacts 5G and 57, thereby simultaneously breaking the circuit to the reversing solenoid and to the lower regulating solenoid 78. When the said lower solenoid 70 is thus deenergized the core 77, lever 73 and contact wheel 75 drop by gravity to their lowermost po-sitions, and the said contact wheel again remains in engagen'ient with the dead contact 72; and when the said reversing solenoid 77 is deenergized just stated, the movable reversing contact C4 drops by gravity into engagement with the lowermcst contacts G0, (31, (32 and G3, thus assuming a position for reversing the current through the motor as soon as the motor circuit is again closed by an upward movement of the contact wheel into engagement with the live members of the contacts 72. It is here also important to note that the variable resistance device above described also affords means for gradually decreasing the resistance and, hence, gadually increasing the current supply to the motor, so that the said motor will be started gradually. f It is, of course, clear that a decreasing resistance in the motor circuit takes place when the contact wheel 7 5 moves upward, and that conversely, an increasing resistance in the motor circuit. takes place when the said contact wheel 7 5 moves downward. It will also be understood that the dash pot 82 assists in prolonging or retarding the movements of the contact wheel 75 from one position t-o another. Then the left hand car l is in a lowered position and the right hand car 4 is in an elevated positicn, and it is desired to cause the said left hand car to travel upward and the righthand car to travel downward, this may be accomplished by raising the left hand controlling rod 52 so as to thereby move the left hand co-ntacts t7 downward into engagement with the cooperating contacts 53 and 54. When the left hand contact levers e7 are thus moved int-o operative positions., the same action takes place as when the said righthand contacts 47 are moved into operative positions, except that the circuit through the motor reversing solenoid 70 remains open and the movable reversing contact G4 remains in its lower position in engagement with the lower cont-acts 60, Gl, G2 and G3, in which position the current through the motor is in a proper direction to cause the motor to raise the left hand car -l and lower the right hand car.

The windlass drum 35 may be Coupled to the windlass shaft 1l at any time, either while the driving sheave 10 is or is not coupled to the said shaft, simply by closing the circuit 89 which supplies the clutch magnets 42. Said circuit 89 is normally broken, but is adapted to be closed by means of any suitable device, such as a push button 89l shown diagrammatically in Fig. 2. l/Vhen the said magnets 4t2 are energized, they rock the armature equipped shafts 38 and thereby cause the head 39 of said shaft to press the clutch shoes 40 tightly into frictional engagement with the opposite sides of the annular channel 36 which is in the hollow drum of the windlass drum 35.

The term switch levers as applied to the levers 4:7 is herein used in a broad sense to include any kind of means for making and breaking the cont-rolling circuits. The term rheostat is used in a broad enough sense to include any kind of a device for varying the resistance of the electric circuit. The term car is also herein used in a broad sense to include any kind of a carrier.

that I claim is:

l. In an electrical hoist, the combination with a pair of cars and a motor having connections for reversely moving the same upward and downward, of electrical connections to said motor including a reversing switch, a rhecstat, a series of fixed contacts and a cooperating movable contact having connections for cutting into and out of the motor circuit more or less of said rheostat, a magnetic controller for said reversing switch, a magnetic controller for said movable contact, and a switch lever for each car having connections to said two magnetic controllers and arranged to be moved into an inoperative position when one of the cars approaches a limit of its upward movement, and the other to be moved into an inoperative position when the other car approaches a limit of its upward movement, substantially as described.

2. In an electrical hoist, the combination with a pair of cars and a motor having connections for moving the same reversely upward and downward, of electrical connections to said motor including a reversing switch, rheostat, fixed contacts and a cooperating movable contact with connections for cutting into and out of the motor circuit more or less of said rheostat, a magnetic controller for said reversing switch, a mag- '-netic controller for said movable contact,

upper and lower pairs of switch levers with electrical connections to said two magnetic contro 1ers, and means for moving said switch levers into inoperative positions, to thereby demagnetize the said two magnetic controllers when the said cars approach limits of their upward movements, substantially as described.

i. In an electrical hoist, the con'ibination with a pair oi" cars and a motor having connections tor reversely moving the same upward and downward, oit electrical connections to said motor including a rheostat, iixed contacts and a colierating movable contact with comiections for cutting into and out oi circuit more or less ot' the rheo stat, a magnetic controller for said movable contact, and switch levers having connections to said magnetic controller, the one switch lever being arranged to be moved into an open position when one of the cars approaches the limit of its upward movement, and the other to be moved into an inoperative position when the other car approaches the limit of its upward n'iovement, substantiallj)7 as described.

4f. In an electrical hoist, the combination with a pair or' cars and a motor with connections for reversel)7 moving the same 'upward and downward, or' electrical connections to said motor including a rheostat, iiXed con tacts and a cooperating movable contact, a magnetic controller for said movable contact including a core and two solenoids cooperating with said core, switch levers arranged in upper and lower pairs and having electrical connections to said two solenoids, one upper and one lower switch lever being arranged to be moved into inoperative po sitions when one of the cars approaches the limit of its upward movement, and the other upper and lower contact switch levers being arranged to be moved into inoperative position when the other car approaches the limit of its upward movement, whereby the said two solenoids will be denergized one after the other, substantially as described.

5. In an electrical hoist, the combination with a pair of cars and a motor having connections for reversely moving the same upward and downward, of electrical connections to said motor including a rheostat and a motor reversing switch, fixed contacts and a cooperating movable contact having connections for cutting into and out of circuit more or less of said rheostat, a magnetic controller for said movable contact, a magnetic controller i'or said reversing switch, a pair of contact levers, one thereof having an electrical connection to the magnetic controller ot said reversing switch, and both thereof having electrical connection to the controller ot said movable Contact, and one of which switch levers is arranged to be moved into inoperative position when one of the cars approaches the limit of its upward movement, and the other of which levers is adapted to be moved into an in operative position when the other car approaches the limit of its upward movel'nent, substantially as described.

In an electrical hoist, the combination with a pair of cars and a` motor having connections for reversely moving the same upward and downward, of electrical connec-A tions to said motor including a reversing switch and a rheostat, fixedO contacts and a cooperating movable contact having connections for cutting into and out of circuit more or less of the rheostat, a magnetic conn troller for said reversing switch, upper and lower solenoids and cooperating core con stituting a controller for said movable contact, upper and lower pairs of switch levers, one of said upper levers having an electrical connection to the magnetic controller of said reversing switch, the two upper switch levers having electrical connection to the lower solenoid, and the two lower switch levers having electrical connection to the upper solenoid ot said contact controller, and one of which upper and one of which lower switch levers is arranged to be moved into an inoperative position when one of the cars approaches the limit of its upward movement, and the other upper and lower of which switch levers are adapted to be moved into inoperative position when the other car approaches the limit of its upward 'movement, substantially as described.

In testimony whereof I aiiix my signature in presence of two witnesses.

GUY C. GRABLE.

Witnesses:

Manin Henn, F. D. MERCHANT. 

